1. Field of the Invention
The present invention relates to a paper money identification method and apparatus, and more particularly to a paper money identification method and apparatus for detecting a slip of paper money being conveyed and identifying the paper money according to its slip.
2. Description of the Related Art
A paper money identification apparatus used for vending machines and the like is configured to recognize a denomination of an inserted paper money and identifies whether it is real or counterfeit and accept real money of acceptable denomination. The paper money is recognized by detecting its feature by means of an optical sensor, a magnetic sensor or the like and comparing the feature with a previously determined standard value. Generally, paper money is discriminated by sensors disposed in the vicinity of a conveying passage for conveying the paper money to detect a feature of the whole paper money being conveyed.
FIG. 6 is a side view showing a schematic structure of the paper money conveying passage.
As shown in FIG. 6, the paper money conveying passage comprises a conveying belt 121 driven by conveying roller 122 rotated by an unshown motor and other conveying rollers 123, 124 and pushing roller 125 disposed at a position to oppose the conveying belt 121. Paper money 100 entering the paper money conveying passage is pushed against the conveying belt 121 by the pushing roller 125 and conveyed by the conveying belt 121 driven by the rotations of the unshown motor.
The paper money conveying passage is provided with identification sensor (optical sensor, magnetic sensor or the like) 161 for detecting a feature of the paper money 100 so to detect the feature of the paper money 100 while it is being conveyed.
As shown in FIG. 7, in order to detect the feature, a conveyed amount of the paper money 100 is specified by virtue of a pulse synchronized with the rotation of the unshown motor output from an encoder or the like mounted on the motor for driving the conveying belt 121, and output of the identification sensor 161 is compared with the standard value of the position corresponding to the conveyed amount of the paper money 100.
When the paper money 100 being conveyed slips (on the conveying belt 121), however, the conveyed amount of the paper money 100 indicated by the pulse synchronized with the rotations of the motor is different from the actual conveyed amount. And output of the identification sensor 161 obtained at the slipped position as shown in FIG. 8 is of a position different from the standard value to be compared. In other words, the paper money 100 is judged to be counterfeit because it has slipped. And a paper money acceptance rate is lowered.
As technologies to prevent a drop of the paper money acceptance rate due to a slip of the paper money, there are proposed xe2x80x9cPaper money identification apparatusxe2x80x9d described in Japanese Patent Application Laid-Open Publication No. 6-84043, xe2x80x9cPaper money identification apparatusxe2x80x9d described in Japanese Patent Application Laid-Open Publication No. 10-255098 and the like.
xe2x80x9cPaper money identification apparatusxe2x80x9d described in Japanese Patent Application Laid-Open Publication No. 6-84043 determines a measuring zone for detecting a feature of paper money and obtains a maximum value and a minimum value in the measuring zone and their mean value to correct an error resulting from the slip. But, its processing for data measurement and calculation is complex.
xe2x80x9cPaper money identification apparatusxe2x80x9d described in Japanese Patent Application Laid-Open Publication No. 10-255098 normalizes the obtained feature in the paper money conveying distance to correct an error resulting from a slip of the paper money. But, the paper money conveying distance is measured by a pulse encoder mounted on the motor, so that no measures can be taken if the pulse as shown in FIG. 8 deviates from the actual conveying distance.
As described above, the feature of the paper money is detected by a variety of sensors to discriminate the paper money, but when the paper money slips during its transfer, the comparison between the detected feature and the standard value to be compared corresponds to the comparison of the feature of the paper money at a different position with the standard value, resulting in judging the paper money as a counterfeit money. Therefore, the paper money acceptance rate is lowered.
There is also proposed a technology to deal with a slip of the paper money during its transfer but its processing is complicated, and it sometimes cannot detect a slip of the paper money depending on a situation that the paper money has slipped.
Under the circumstances described above, it is an object of the invention to provide a paper money identification method and apparatus which can detect the occurrence of a slip when a paper money slips during its transfer and discriminate the paper money according to the slip of the paper money.
To achieve the aforesaid object, the invention comprises a paper money identification method for identifying paper money by conveying an inserted paper money along a paper money conveying passage by means of conveying belts and reading identification data of the paper money by a paper money identification sensor disposed above the paper money conveying passage, wherein the conveying belts are driven by a conveying motor, the paper money being conveyed along the paper money conveying passage is pushed by pushing rollers, a displaced conveying position of the paper money is detected according to a motor signal synchronized with the rotation of the conveying motor and a roller signal synchronized with the rotation of the pushing rollers, and the identification data is corrected according to the detected displaced conveying position of the paper money to identify the paper money.
The invention also comprises a method wherein the motor signal and the roller signal are pulse signals, and the detection is performed by comparing pulse widths of the motor and roller signals.
The invention further comprises a paper money identification method for identifying paper money by conveying an inserted paper money along a paper money conveying passage by means of conveying belts and reading identification data of the paper money by a paper money identification sensor disposed above the paper money conveying passage, wherein the conveying belts are driven by a conveying motor, the paper money being conveyed along the paper money conveying passage is pushed by pushing rollers, the identification data is sampled according to a roller signal synchronized with the rotation of the pushing rollers, and the paper money is identified according to the sampled identification data.
The invention further composes a paper money identification apparatus for identifying paper money by conveying an inserted paper money along a paper money conveying passage by means of conveying belts and reading identification data of the paper money by a paper money identification sensor disposed above the paper money conveying passage, comprising: a conveying motor for driving the conveying belts; pushing rollers which rotate in contact with the paper money being conveyed along the paper money conveying passage; and detection means for detecting a displaced conveying position of the paper money according to a motor signal synchronized with the rotation of the conveying motor and a roller signal synchronized with the rotation of the pushing rollers, wherein the identification data is corrected according to a detection output of the detection means to identify the paper money.
The invention also directed to the invention wherein the motor signal and the roller signal are pulse signals, and the detection means detects a difference of pulse width between the motor signal and the roller signal as a displacement of transfer of the paper money.
The invention further comprises a paper money identification apparatus for identifying paper money by conveying an inserted paper money along a paper money conveying passage by means of conveying belts and reading identification data of the paper money by a paper money identification sensor disposed above the paper money conveying passage, comprising: a conveying motor for driving the conveying belts; pushing rollers which rotate in contact with the paper money being conveyed along the paper money conveying passage; and sampling means for sampling the identification data according to a roller signal synchronized with the rotation of the pushing rollers, wherein identification of the paper money is carried out according to the identification data sampled by the sampling means.
The invention is also directed to the sampling means which comprises an encoder for generating a pulse signal synchronized with the rotation of the pushing rollers.
According to the invention, the motor pulse synchronized with the rotation of the motor for driving the conveying belts and the roller pulse synchronized with the rotation of the pushing rollers for pushing the paper money to the conveying belts are compared for their pulse widths and when there is a difference between the pulse widths, it is detected that the paper money has slipped. Therefore, a slip of the paper money can be detected without fail.
And, the feature of the paper money is detected in synchronization with the roller pulse and the paper money is identified according to the feature detected. Therefore, even when the paper money slips, its feature corresponding to a predetermined position of the paper money can be detected, and misidentification due the slip of the paper money can be reduced. And, a paper money reception rate can be improved.